Grapple device



Oct. 13, 1964 M. L. CONRAD GRAPPLE DEVICE Filed Dec. 22, 1961 2Sheets-Sheet 1 @ccumulutor) FIG. 4

iNvENToR Marcus L. Conrad BY W M ATTORN EY M. L- CONRAD GRAPPLE DEVICEOct. 13, 1964 2 Sheets-Sheet 2 Filed Dec. 22, 1961 INVENTOR Marcus L.Conrad fikmwe am ATTORNEY United States Patent 3,152,706 GRAPPLE DEVICEMarcus L. Conrad, Stevensville, Mich, assignor to Clark EquipmentCompany, a corporation of Michigan Filed Dec. 22, 1961, Ser. No. 161,5874 Claims. (Cl. 214-147) This invention relates to material handlingdevices, and more specifically to tractor mounted grapples for handlingheavy objects of irregular shape and size, such as large pieces ofquarried stone and the like.

It is known to use very large pieces of stone as riprap for dams, dikesand causeways, and such stones may weigh as much as 30,000 lbs. each andin a typical case may have dimensions which are roughly 6 ft. x 6 ft. x8 ft. The handling of such rocks presents a diflicult problem,especially so when the rocks are irregular in shape and must be pickedup, transported, and then deposited in or on a conveyance such as aheavy truck or railroad car. When such rocks are to be movedconsiderable distances they are commonly carried in gondola-type railroad cars which typically may have sides 8 ft. or more in height abovethe ground. Moreover, it will be appreciated that a rock of the size andweight mentioned must be deposited gently in the railroad car or otherconveyance, since dropping such a rock even a few inches could badlydamage the conveyance into which it is being loaded. It is alsonecessary, of course, to unload such rocks from the conveyance againnear the site where the riprap is to be placed, after which they mustagain be transported and then put into final position.

Prior to the present invention, to the best of my knowl edge, there wasno single device available which was capable of handling expeditiouslysuch heavy objects of irregular shape and size as describedhereinbefore, although it was known prior to the present invention touse other types of grapples in conjunction with cranes, tractors andother machines. With my device, as many as forty rocks weighing anaverage of 9.1 tons apiece have been moved 110 feet in one hour. Inanother situation a piece of granite weighing 31,200 lbs. wastransported from a quarry floor to a rail heading 2,700 ft. away in lessthan 6 minutes.

The object of the present invention is to provide a vehicle mountedgrapple device which is capable of picking up, transporting, loading andunloading very large rocks of irregular size.

In carrying out my invention in a preferred embodiment, I provide agenerally downwardly disposed grapple pivotally connected to theforwardly extending boom arms of a wheeled tractor. The grapple includesa laterally elongated grapple arm and a pair of laterally spaced grapplearms disposed in diverging relation relative to the elongated grapplearm and pivotally connected thereto in confronting relation therewith toform an inverted generally U-shaped opening therebetween.

The above object and other objects, features and advantages of myinvention will become more readily apparent to persons skilled in theart from the following detailed description when taken in conjunctionwith the accompanying drawing wherein:

FIGURE 1 is a perspective view of a tractor embodying the invention,

FIGURE 2 is a side elevational view of my invention on a larger scaleshowing the grapple device and a portion of the tractor boom arms,

FIGURE 3 is a top plan view of the same portion of the invention as FIG.2.

FIGURE 4 is a schematic drawing showing the fluid circuit for actuatingthe pair of diverging grapple arms, and

3,152,705 Patented Oct. 13, 1964 ice FIGURE 5 is a fragmentary view ofan enlarged scale showing to advantage one of the C-shaped retainingrings.

Referring to FIG. 1, the numeral 10 denotes generally a tractor having apair of front drive wheels 12 and a pair of rear drive-steer wheels 14(only one of which is shown). The tractor 10 includes a body 16, asteering control wheel 18 located at an operators station and a pair offorwardly extending parallel boom arms 20 pivotally connected to body 16at 22 and rigidly connected adjacent their forward ends by a transversebrace member 26. The boom arms 20 are arranged to be pivoted aboutpivotal connections 22 by means of upwardly and forwardly inclinedpiston and cylinder type fluid actuators 24 (only one of which is shown)pivotally connected at one end to the respective boom arms 20intermediate the ends thereof and pivotally connected at their otherends to body 16.

Referring also now to FIGS. 2 and 3, a generally downwardly openinggrapple 28 is pivotally connected to the forward ends of boom arms 20.The grapple 28 includes a rear laterally elongated arcuate grapple arm30 pivotally connected to boom arms 20 and a pair of front arcuatelaterally spaced apart grapple arms 32 pivotally connected to grapplearm 30 in confronting relation therewith to form an inverted generallyU-shaped opening between the grapple arms in the positions illustratedin FIGS. 1 and 2.

The elongated grapple arm 30 includes a pair of laterally spaced partend plates 34 each having a forwardly curved upper portion 36 and atoothed or serrated lower portion 38 on the forward edge thereof. Theend plates 34 are rigidly secured together to form elongated grapple arm30 by means of three vertically spaced apart transversely extending andhorizontally disposed brace members 40 of rectangular cross-section.Brace members 40 are inclined rearwardly, as shown, to present upwardlyfacing inclined surfaces 41 to the load to aid in cradling the loadbetween rear grapple arm 30 and the forward grapple arms 32. The corners40a of brace members 40 which thus engage the load likewise are usefulin holding the load since these corners form sharp edges which tend tobite into the load and aid in gripping a load between grapple arm 30 andthe serrations 114 on forward grapple arms 32. The upper portions 36 ofend plates 34 are rigidly secured together by means of a pair oflongitudinally spaced apart rectangular brace members 42 that extendtransversely therebetween. Also extending between upper portion 36 is agenerally horizontally disposed support plate 44 which abuts the upperedges of brace plates 42. In addition to serving as a brace memberbetween end plates 34, support plate 44 also serves to support grapplearms 32 as will be explained in greater detail hereinafter. Members 40,42 and 44 preferably are secured to end plates 34 by welding, althoughother suitable means of connection may be used.

At this point it will be appreciated that grapple arm 30 is an elongatedunitary structure and provides a large area that is well adapted toengage and grip an object of irregular shape since the brace members 40provide central engagement between end plates 34 which serve to preventthe object engaged from slipping sideways out of contact with grapplearm 30. Further, end plates 34 provide through the serrated portions 38means for gripping an irregular surface, as do inclined brace members40. Grapple arm 30 is pivotally connected to boom arms 20 by means of apair of generally vertically disposed double ended bracket connectors52. Each bracket connector 52 includes an outboard support plate 46disposed outwardly of the adjacent end plate 34 in spaced relationthereto and secured thereto by means of a rectangular spacer member 48and an upwardly extending triangular member 50 as best shown in FIGS. 2and 3. The lower ends of bracket connectors 52 are adapted to receiverespectively the forward ends of boom arms 20 between outboard support46 and end plate 34 whereby grapple arm 31 is pivotally connected toboom arms 20 by means of the pair of pins 58 passing respectivelythrough plates 34 and 46 and boom arms 20. Referring to FIG. 5, each pin58 is held from both axial and rotational movement by means of aO-shaped retainer ring 611 which engages a pair of diametricallydisposed parallel slots 62 adjacent the end of pin 58 and is secured tothe adjacent outboard support plate 46 by means of a plurality ofmachine screws 64. Due to the pin and bracket connections 58, 52 thegrapple arm 30 is pivotal on boom arms 26 about a horizontally disposedaxis through pins 58 transverse to tractor 10.

The grapple arm 39 is actuatable about connections 52, 53 by means of apair of double acting fluid actuators 66 including, respectively, acylinder 68 within which is slidably disposed a piston (not shown) and apiston rod 70 attached to the piston and extending outwardly through oneend of cylinder 68. The cylinders 63 are pivotally connected,respectively, to boom arms 2% by pin and bracket connections 74 andpiston rods 70 are pivotally connected, respectively, to the upper endsof bracket connectors 52 by means of the pins 76 passing respectivelythrough plates 46 and t and rods 70. Each pin 76 is held from axial androtational movement by means of a C-shaped retaining ring 78 engaging apair of diametrically disposed parallel slots 80 adjacent one endthereof, the same as ring 60 which is shown to advantage in FIG. 5. TheC-shaped retaining ring 78 is secured to the adjacent outboard supportplate 46 by means of a plurality of machine screws 82.

Secured to support plate 44 is a pair of forwardly extending actuatorand grapple arm supports 84 which are disposed to angle outwardly aboutdegrees with respect to the horizontal longitudinal axis of body 16, asshown in FIG. 3. Each actuator and grapple arm support 84 includes apair of spaced apart parallel plates 86 of generally L-shape having anelongated base leg 58 and an upwardly extending vertical leg 93. Plates86 are secured to support plate 44 by any suitable means, such aswelding, and reinforced by a spacer plate 92 (only one of which isshown) disposed between plates 86 and secured thereto, preferably bywelding. The grapple arms 32 are disposed between respective pairs ofparallel plates 86 adjacent the end of base legs $8 and pivotallyconnected thereto by means of a pin 94.

A pair of double acting piston and cylinder type fiuid actuators 1G0serve respectively to pivot grapple arms 32 about pins 94. Each fluidactuator 1% includes a cylinder 102, a piston 103 (FIG. 4) slidablydisposed in the cylinder and a piston rod 164 connected to the pistonand extending outwardly through one end of cylinder 192. The end ofcylinder M12 is disposed between the vertical legs 90 of parallel plates86 and pivotally connected there- 'to by means of a pin 1656. The pistonrods 1114 are pivotally connected respectively to grapple arms 32 bymeans of a pin and bracket connection 112.

Each grapple arm 32 is generally arcuate in shape and has the serratedor toothed portion 114 adjacent the lower ends thereof and in facingrelation with toothed portion 38 of end plates 34. Because of the angleat which actuator and grapple arm supports 34 are disposed, the ends ofgrapple arms 32 tend to move closer together as grapple arms 32 areactuated toward grapple arm 30, and to move further apart as grapplearms 32 are actuated away from grapple arm 31). In other words, thelateral distance between the ends of grapple arms 32 decreases as theyapproach the grapple arm 3%. This arrangement of grapple arms 32 has theadvantage of permitting grapple 28 to engage objects of widely varyingsize, and also tends to pull the object being engaged toward the centerof the grapple with the result that the object being engaged is lesslikely to slip sideways out of the grapple.

Referring now to FIG. 4, the hydraulic circuit for operating fluidactuators 106 is shown in schematic form. A pump 116 which preferably isdriven by the engine of the vehicle 10, pressurizes fluid drawn from asump or reservoir 118 via a conduit 120. The pressurized fluid isdirected to a control valve 122 by a conduit 124 which contains apressure relief valve 126 vented back to the reservoir 118 by a conduit128 to regulate the pressure in conduit 124. The front ends of cylinders102 are connected in parallel by a conduit 13th which is connected tovalve 122 via a conduit 132. Also, the rear ends of cylinders 102 areconnected in parallel by a conduit 134 which is connected to valve 122by a conduit 136. Connected to conduit 136 is an accumulator 138, thefunction of which will be explained shortly. The valve 122 also isconnected to reservoir 118 by a conduit 146. The valve 122 isselectively actuatable between a grapple open position in which itcommunicates conduit 124 with conduit 132 and conduit 136 with conduitso that piston rods 104 move to the right as shown in FIG. 4 and pivotgrapple arms 32 in a clockwise direction, as seen in FIGS. 1 and 2; agrapple closed position in which conduit 124 is connected to conduit 136and conduit 132 is connected to conduit 140 with the result thatpressure fluid is supplied to the back side of pistons 103, thus causingpiston rods 104 to move to the left, as seen in FIG. 4, so that grapplearms 32 are pivoted in a counterclockwise direction, as viewed in FIGS.1 and 2, to engage an object to be lifted; and a hold position in whichconduits 132 and 136 are in communication with neither conduits 124 norconduit 140. When the grapple has engaged an object and the valve 122 isin the hold position the accumulator 138 serves to maintainsubstantially full pressure on pistons 103, since even a slight loss ofpressure which otherwise would be possible through leakage around valve122 and pistons 103 might cause the grapple to drop the object engagedthereby.

-While I have not described in detail the fluid circuitry associatedwith actuators 66 for pivoting grapple 28 about the ends of boom arms 20and piston and cylinder actuators 24 for pivoting the boom arms 20 aboutpoint 22, it will be appreciated that these actuators are of thedouble-acting type, i.e., arranged to have fluid pressure communicatedto either side of the piston to cause the piston rod to either extend orretract. Actuators 66 and 24 are connected respectively to a source ofpressure fluid and a fiuidreservoir by means of suitable fluidcircuitry, including control valves conveniently located at theoperators station for controlling the extension and retraction of thepiston rods of the actuators 66 and 24.

In operation, the grapple 28 is positioned so that the object to beengaged is disposed within the U-shaped opening between grapple arms 30and $2. The object is then engaged by moving valve 122 to the grappleclosed position, whereby grapple arms 32 are pivoted toward grapple arm30 with the result that the object to be engaged is forcefully heldbetween grapple arms 30 and 32. It will be noted at this point that theparallel fluid connection between grapple arms 32 permits one of them tomove a greater distance than the other, if necessary, to engage anobject having an irregular shape. After the load is engaged, the valve122 is actuated to its hold position so that grapple arms 32 willmaintain forceful contact with the object engaged. Now the boom arms 20can be actuated to lift the grapple, along with the load, slightly offthe ground. With the load thus raised the tractor is used to transportthe load to the desired location where the load may be redeposited uponthe ground and the grapple released. Or the load may be deposited, forexample, within a gondola-type railroad car by raising the boom arms toa height at which the grapple and the engaged object clears the side ofthe railroad car-including tilting the grapple partially back over theboom arms 20 by means of actuators 66 if necessary-then moving thetractor slightly forward to bring the load over the railroad car, atwhich point the boom arm actuators 24 and actuators 66, if used areactuated to cause the grapple to lower the load into the car. When theload is resting upon the bottom of the car the grapple arms 32 areactuated to release the load by moving valve 122 to the grapple releaseposition. The grapple is then raised and the tractor it) is backed awayfrom the railroad car.

The above-detailed description is illustrative only, and should not beconstrued as limiting the scope of my invention. The scope of myinvention should be determined from the following appended claims whentaken in view of the prior art.

I claim:

1. For use with a tractor having a pair of boom arms, a downwardlyopening grapple comprising a laterally elongated grapple arm adapted tobe pivotally connected to the boom arms, said elongated grapple armincluding a pair of arcuate end plates disposed in laterally spacedapart relation and laterally extending brace means connecting said endplates, thus forming a unitary laterally elongated structure, a pair oflaterally spaced apart arcuate grapple arms pivotally connected to saidelongated grapple arm in confronting relation therewith, said grapplearms defining an inverted generally U-shaped opening therebetween, saidpair of grapple arms being disposed in diverging relation relative toeach other so that the axes about which they pivot are non-parallel, andmeans for actuating said pair of grapple arms pivotally relative to saidelongated grapple arm, said means including a pair of fluid actuatorsconnected respectively to said pair of grapple arms and connected inparallel to a source of pressure fluid.

2. A grapple comprising a laterally elongated grapple arm, saidelongated grapple arm including a pair of laterally spaced apart endplates and a plurality of back- Wardly inclined brace members extendinghorizontally between and connecting said end plates, a pair of grapplearms pivotally connected to said elongated grapple arm in laterallyspaced apart and confronting relation therewith so as to define aninverted generally U-shaped laterally elongated opening therebetween,said pair of grapple arms being disposed in diverging relation to eachother so that the axes about which they pivot are nonparallel, and apair of fluid motors for actuating respec tively said pair of grapplearms about their pivotal connections, said fluid motors being connectedin parallel to a source of pressure fluid.

3. For use with a tractor having a pair of boom arms, a downwardlyopening grapple comprising a laterally elongated grapple arm adapted tobe pivotally connected to the boom arms, said elongated grapple armincluding a pair of generally vertically disposed arcuate end platesdisposed in laterally spaced apart relation and having serrations on thelower portion of the concave surfaces thereof, laterally extending,rearwardly inclined brace members connecting said end plates, said bracemembers having a sharp edge, and a laterally extending support plateconnecting the upper ends of said end plates, thus forming with said endplates and brace members a unitary laterally elongated structure, a pairof generally vertically disposed, laterally spaced apart grapple armspivotally mounted on said support plate in confronting relation withsaid elongated grapple arm and having serrations on the lower portion ofthe concave surfaces thereof, said grapple arms defining an invertedgenerally U-shaped opening therebetween, said pair of grapple arms beingdisposed in diverging relation relative to each other such that theincluded angle therebetween is substantially 20, and a pair ofdouble-acting piston and cylinder type fluid motors connected betweensaid pair of grapple arms and said elongated grapple arm for pivotingsaid pair of grapple arms relative to said elongated grapple arm, saidfluid motors being connected in parallel with a source of fluidpressure.

4. A rock handling tractor vehicle comprising a body portion having alongitudinally extending horizontally disposed axis, a pair of forwardlyextending boom arms located in symmetrical relation on opposite sides ofthe said axis, the said arms being pivoted at their rearward ends on thesaid body portion, a first pair of hydraulic actuators connectedrespectively between the said body portion and the said boom arms forraising and lowering the forward ends thereof, a downwardly openinggrapple pivotally connected to the said forward ends of the boom arms,the said grapple including a pair of generally vertically disposed endplates located in laterally spaced apart relation and pivotallyconnected respectively to the said boom arms, the said end plates havingcurved forwardly extending portions at the tops thereof and serrationson the front surfaces thereof near the lower ends, a plurality oflaterally extending brace members rigidly connected between the said endplates rearwardly of the said front surfaces, each of the said bracemembers presenting a forwardly disposed sharp edge and a slantedupwardly facin surface adjacent the said edge, and a laterally extendingsupport plate rigidly connected between the said curved upper ends ofthe said end plates, the said end plates and brace members and supportmember forming a unitary transversely extending rear arm structure forthe said grapple, a second pair of hydraulic actuators pivotallyconnected respectively between the said end plates and the said boomarms for pivoting the said rear grapple arm structure with respect tothe said boom arms about a transverse horizontal axis, a pair of curvedgrapple arms pivotally mounted on the said support plate in generallyvertically disposed laterally spaced apart relation and in confrontingrelation with the said rear grapple arm structure, the said pair ofgrapple arms having serrations on the rearward surfaces of the lowerportions thereof, the said pair of grapple arms defining a generallyU-shaped inverted opening between them and the said rear grapple armstructure, the said pair of grapple arms being disposed symmetricallywith respect to the said longitudinal axis and in forwardly divergingrelation relative to each other, each making an angle of approximately10 with a vertically disposed plane through the said longitudinal axis,a third pair of hydraulic actuators connected respectively between thesaid pair of grapple arms and the said support plate for pivoting thesaid grapple arms toward and away from the said rear grapple armstructure, a source of pressurized hydraulic fluid carried by the saidbody portion, and means connecting the said third pair of hydraulicactuators in parallel to the said source of pressurized hydraulic fluidwhereby the said pair of grapple arms may be operated simultaneously orindividually if one of them is restrained from movement.

References Cited in the file of this patent UNITED STATES PATENTS

4. A ROCK HANDLING TRACTOR VEHICLE COMPRISING A BODY PORTION HAVING ALONGITUDINALLY EXTENDING HORIZONTALLY DISPOSED AXIS, A PAIR OF FORWARDLYEXTENDING BOOM ARMS LOCATED IN SYMMETRICAL RELATION ON OPPOSITE SIDES OFTHE SAID AXIS, THE SAID ARMS BEING PIVOTED AT THEIR REARWARD ENDS ON THESAID BODY PORTION, A FIRST PAIR OF HYDRAULIC ACTUATORS CONNECTEDRESPECTIVELY BETWEEN THE SAID BODY PORTION AND THE SAID BOOM ARMS FORRAISING AND LOWERING THE FORWARD ENDS THEREOF, A DOWNWARDLY OPENINGGRAPPLE PIVOTALLY CONNECTED TO THE SAID FORWARD ENDS OF THE BOOM ARMS,THE SAID GRAPPLE INCLUDING A PAIR OF GENERALLY VERTICALLY DISPOSED ENDPLATES LOCATED IN LATERALLY SPACED APART RELATION AND PIVOTALLYCONNECTED RESPECTIVELY TO THE SAID BOOM ARMS, THE SAID END PLATES HAVINGCURVED FORWARDLY EXTENDING PORTIONS AT THE TOPS THEREOF AND SERRATIONSON THE FRONT SURFACES THEREOF NEAR THE LOWER ENDS, A PLURALITY OFLATERALLY EXTENDING BRACE MEMBERS RIGIDLY CONNECTED BETWEEN THE SAID ENDPLATES REARWARDLY OF THE SAID FRONT SURFACES, EACH OF THE SAID BRACEMEMBERS PRESENTING A FORWARDLY DISPOSED SHARP EDGE AND A SLANTEDUPWARDLY FACING SURFACE ADJACENT THE SAID EDGE, AND A LATERALLYEXTENDING SUPPORT PLATE RIGIDLY CONNECTED BETWEEN THE SAID CURVED UPPERENDS OF THE SAID END PLATES, THE SAID END PLATES AND BRACE MEMBERS ANDSUPPORT MEMBER FORMING A UNITARY TRANSVERSELY EXTENDING REAR ARMSTRUCTURE FOR THE SAID GRAPPLE, A SECOND PAIR OF HYDRAULIC ACTUATORSPIVOTALLY CONNECTED RESPECTIVELY BETWEEN THE SAID END PLATES AND THESAID BOOM ARMS FOR PIVOTING THE SAID REAR GRAPPLE ARM STRUCTURE WITHRESPECT TO THE SAID BOOM ARMS ABOUT A TRANSVERSE HORIZONTAL AXIS, A PAIROF CURVED GRAPPLE ARMS PIVOTALLY MOUNTED ON THE SAID SUPPORT PLATE INGENERALLY VERTICALLY DISPOSED LATERALLY SPACED APART RELATION AND INCONFRONTING RELATION WITH THE SAID REAR GRAPPLE ARM STRUCTURE, THE SAIDPAIR OF GRAPPLE ARMS HAVING SERRATIONS ON THE REARWARD SURFACES OF THELOWER PORTIONS THEREOF, THE SAID PAIR OF GRAPPLE ARMS DEFINING AGENERALLY U-SHAPED INVERTED OPENING BETWEEN THEM AND THE SAID REARGRAPPLE ARM STRUCTURE, THE SAID PAIR OF GRAPPLE ARMS BEING DISPOSEDSYMMETRICALLY WITH RESPECT TO THE SAID LONGITUDINAL AXIS AND INFORWARDLY DIVERGING RELATION RELATIVE TO EACH OTHER, EACH MAKING ANANGLE OF APPROXIMATELY 10* WITH A VERTICALLY DISPOSED PLANE THROUGH THESAID LONGITUDINAL AXIS, A THIRD PAIR OF HYDRAULIC ACTUATORS CONNECTEDRESPECTIVELY BETWEEN THE SAID PAIR OF GRAPPLE ARMS AND THE SAID SUPPORTPLATE FOR PIVOTING THE SAID GRAPPLE ARMS TOWARD AND AWAY FROM THE SAIDREAR GRAPPLE ARM STRUCTURE, A SOURCE OF PRESSURIZED HYDRAULIC FLUIDCARRIED BY THE SAID BODY PORTION, AND MEANS CONNECTING THE SAID THIRDPAIR OF HYDRAULIC ACTUATORS IN PARALLEL TO THE SAID SOURCE OFPRESSURIZED HYDRAULIC FLUID WHEREBY THE SAID PAIR OF GRAPPLE ARMS MAY BEOPERATED SIMULTANEOUSLY OR INDIVIDUALLY IF ONE OF THEM IS RESTRAINEDFROM MOVEMENT.